问题
I have a PostgreSQL DB, where I use materialized views. The problem occurs when I try to refresh these materialized views.
REFRESH MATERIALIZED VIEW product_cat_mview;
REFRESH MATERIALIZED VIEW productsforproject;
My solution is, when the user want to see updated data, he should click a "refresh button" on the web page, but this takes about 50s (on a local connection and about 2 minutes from the application server) and all this time the user has to wait, which is not good.
Now I should create a solution to automatically refresh these materialized views every 10 minutes. I have created a Java solution with multithreading. But I have one problem.
The first query
REFRESH MATERIALIZED VIEW CONCURRENTLY product_cat_mview;
works correct, but the second
REFRESH MATERIALIZED VIEW CONCURRENTLY productsforproject;
complains that I need to create a unique index. I tried create index, unique index etc. that I found in google, but I still get the message to "Create unique index".
回答1:
You will have to create a unique index on the materialized view itself.
This would look like this:
CREATE UNIQUE INDEX ON productsforproject (id);
Replace id with a suitable unique key column or a (comma separated) combination of such columns.
来源：https://stackoverflow.com/questions/41803781/refresh-materialized-views-with-concurrency